The way of the elders. Theravāda is oldest existing, most orthodox form of Buddhism. The teachings and practices are virtually unchanged from the time of the Buddha, including the monastic orders and the rules for the monastic communities and the emphasis on meditation and the teachings of the Eightfold Middle Path.
Theravādins have preserved their version of Gautama Buddha's teaching in the Pāli Canon.
Vipassana movement is a modern development of Theravāda Buddhism.